Feeding Ecology of Two Plecopterans in Low Order Andean-Patagonian Streams

Abstract

Feeding plasticity of the Andean plecopteran Klapopteryx kuscheli and Notoperla archiplatae larvae was assessed through a field experiment using enclosures. K. kuscheli has previously been described as a shredder and N. archiplatae as a scraper. Further information on gut contents from different populations supported those results. In the experiment, larvae of both species were exposed to contrasting food items: leaf litter and periphyton. Consumption, growth and the efficiency of food conversion were measured. K. kuscheli was able to feed on periphyton, though it did not grow. N. archiplatae failed to feed on leaf litter. While K. kuscheli might be considered a facultative shredder, N. archiplatae functions as a specialist scraper. The natural distribution and seasonal abundance in two small streams showed contrasting habitat use of both species. N. archiplatae inhabited high velocity runs and riffles underneath large substrates while K. kuscheli presented a higher habitat plasticity. Implications of those results for ecosystem function are discussed.

Diet of invertebrates sampled in leaf-bags incubated in a tropical headwater stream

“…This study corroborates the recent literature (ROSI-MARSHALL & WALLACE 2002, BENSTEAD & PRINGLE 2004, MOORE et al 2004, MOTTA & UIEDA 2004, BAXTER et al 2005, CHESHIRE et al 2005, LANCASTER et al 2005, ALBARIÑO & VILLANUEVA 2006) that emphasizes the great importance of organic matter as food resource for the macroinvertebrates community. However, the high diversity of the macrofauna associated to litter compared to the low diversity of shredders suggests that the coarse particulate organic matter is used more as substrate than as direct food, becoming an important food source to macroinvertebrates after its decomposition until fine particles.…”

“…For ALBARIÑO & VILLANUEVA (2006), the hydraulic conditions and the food availability were responsible for a higher density of the plecopteran Klapopteryx kuscheli Illies, 1960, a specialist shredder. In the same way, our results suggest that food availability (high leaf litter availability in the forested area) and stream retentiveness (high leaf litter standing stock during the rainy season) are suitable habitat traits to Phylloicus.…”

“…ABELHO 2001). The relationship between this basal resource and the aquatic invertebrates is assessed mainly by gut content studies (BASAGUREN et al 2002, ROSI-MARSHALL & WALLACE 2002, BENSTEAD & PRINGLE 2004, MOTTA & UIEDA 2004, CHESHIRE et al 2005, LANCASTER et al 2005, ALBARIÑO & VILLANUEVA 2006.…”

Primary consumers and resources: Annual variation in two contrasting reaches of a Patagonian mountain stream

“…In accordance to the model of leaf litter-detritivore dynamics in streams proposed by Cummins et al (1989), there was a peak of shredders biomass in August, three months after leaf litter input. This pattern was also found in a nearby stream, where the biomass of the shredder K. kuscheli peaked in winter (Albarin˜o and Dı´az Villanueva, 2006). The delay would reflect the timing of N. pumilio leaf litter conditioning, which has been estimated in two to three months (Albarin˜o and Balseiro, 2002).…”

“…In many headwater streams of Patagonian Andes, the main primary consumers in terms of biomass are shredders and scrapers (Vela´zquez and Miserendino, 2003;Albarin˜o and Dı´az Villanueva, 2006;Miserendino, 2007). These two FFGs greatly differ in their ecological dynamics.…”